Albuminuria in Type 1 (insulin-dependent) diabetes is not only an indication of renal disease, but a new, independent risk-marker of proliferative retinopathy and macroangiopathy. The coincidence of generalised vascular dysfunction and albuminuria, advanced mesangial expansion, proliferative retinopathy, and severe macroangiopathy suggests a common cause of albuminuria and the severe renal and extrarenal complications associated with it. Enzymes involved in the metabolism of anionic components of the extracellular matrix (e.g. heparan sulphate proteoglycan) vulnerable to hyperglycaemia, seem to constitute the primary cause of albuminuria and the associated complications. Genetic polymorphism of such enzymes is possibly the main reason for variation in susceptibility.

A follow-up of 1475 Type 1 (insulin-dependent) diabetic patients diagnosed before 1953 (815 males, 660 females) and before the age of 31 years was conducted. All patients were seen at the Steno Memorial Hospital and were referred from all parts of Denmark; 91 (6%) could not be traced. The rest (94%) were followed until death or for at least 25 years; 249 (17%) were followed for greater than 40 years. Clinical diabetic nephropathy developed in 531 (41%) of the 1303 patients in whom sufficient information was available regarding proteinuria. Other causes of proteinuria were found in 3%, and 57% did not develop persistent proteinuria. The prevalence of diabetic nephropathy was 21% after 20-25 years of diabetes duration followed by a decline to 10% after 40 years. Two incidence peaks of the onset of proteinuria were seen, one after 16 and another after 32 years duration of diabetes and was low after 35 years duration. The cumulative incidence was 45% after 40 years of diabetes. A male preponderance was seen among patients with nephropathy. A significant difference in the pattern of annual incidence rates of diabetic nephropathy was seen, when groups with onset of diabetes before 1933, between 1933-1942, and 1943-1952, respectively, were compared. An association between daily insulin requirement and nephropathy incidence was found. Patients with nephropathy had a much poorer survival than those without proteinuria; 40 years after onset of diabetes, only 10% of patients who developed nephropathy were alive, whereas greater than 70% of patients who did not develop nephropathy survived.(ABSTRACT TRUNCATED AT 250 WORDS)

We followed 1,134 patients with Type 1 (insulin-dependent) diabetes, diagnosed between 1933 and 1952, until 1982 or death or until their emigration. Their age at onset of diabetes was under 31 years. Information concerning the development of persistent proteinuria was sought in every case. In 104 cases, the data were either questionable or the patient could not be traced. Twenty-nine patients developed non-diabetic proteinuria. Among the remaining 1,001 patients, 406 developed persistent proteinuria (350 died) and 595 did not (166 died). The incidence of persistent proteinuria was highest among men; it decreased with increasing year of diabetes onset from 1933 to 1952, and decreased with increasing age at onset. The relative mortality was extremely high among patients with persistent proteinuria, increasing to a maximum of about 100 at age 35 years. Patients not developing proteinuria had a relatively constant low relative mortality of about 2. The decreasing incidence of persistent proteinuria and the decreasing mortality with increasing calendar year of diabetes onset resulted in a 50% increase in life-expectancy among patients diagnosed in 1950 compared with patients diagnosed in 1935. In patients who developed persistent proteinuria, relative mortality was higher in women than men at all ages. In patients who did not develop proteinuria, relative mortality was similar in men and women after the age of 35. Uraemia was the main cause of death in patients with persistent proteinuria, although cardiovascular deaths were more frequent than in patients without proteinuria. Thus, proteinuria is associated not only with death from uraemia but also from cardiovascular disease.(ABSTRACT TRUNCATED AT 250 WORDS)

No abstract

Patients with Type 1 (insulin-dependent) diabetes without proteinuria were studied to define those patients who will later develop persistent proteinuria (more than 0.5 g protein/24 h). Two investigations were performed; 71 patients were studied longitudinally for 6 years and another 227 patients were studied cross-sectionally. All were less than 50 years of age and had developed diabetes before the age of 40 years. At entry into the study they had no proteinuria (Albustix method), had normal blood pressure and urinary albumin excretion rates less than 200 micrograms/min (normal less than or equal to 20 micrograms/min). The best predictor of persistent proteinuria or an albumin excretion rate greater than 200 micrograms/min was the initial urinary albumin excretion rate. During the longitudinal study, seven patients with an urinary albumin excretion rate of more than 70 micrograms/min at the start of the study developed persistent proteinuria or an albumin excretion rate greater than 200 micrograms/min. In contrast, only three out of the remaining 64 patients with urinary albumin excretion rate less than or equal to 70 micrograms/min developed urinary albumin excretion rate greater than 200 micrograms/min. Patients with an urinary albumin excretion rate greater than 70 micrograms/min are thus at risk of developing diabetic nephropathy. We designate this stage of renal involvement incipient nephropathy. Patients with incipient nephropathy were further characterized in the cross-sectional study. Compared with normoalbuminuric patients, patients with incipient nephropathy had increased systolic and diastolic blood pressure, but normal serum creatinine. The glomerular filtration rate was higher than normal in patients with incipient nephropathy though not different from that of normoalbuminuric patients.

No abstract

A follow-up on three hundred and seven patients diagnosed before 1933 and before the patient was thirty-one years old was conducted as of 1.1. 1973, i.e. after at least forty years of diabetes. All patients were seen at the Steno Memorial hospital and were referred from all parts of Denmark. A small proportion of the patients (5.9%) could not be traced. Of the remaining two hundred and eightynine patients 40% were alive. Three-hundred and six patients were insulin dependent, 87% being treated with insulin twice daily. More than 50% survived their diabetes for more than thirty-five years. The mortality rate was 2-6 times that in an age-and sexmatched non-diabetic population. In 31% of the deceased patients the cause of death was uraemia; in 25% myocardial infarction. The excess mortality among patients exhibiting persistent proteinuria before forty years of diabetes was 3-4 times higher than in patients who did not have proteinuria after forty years. 167/o of the whole study population became blind, and another 14% had severely impaired vision; 21% exhibited objective signs of myocardial infarction, 10% of stroke, and 12% had gangrene or had undergone amputation of the foot or lower leg; 38% had proteinuria and 22% uraemia. Death with or from hypoglycaemia was more common than death in ketoacidotic coma. Clinical manifestations of late diabetic complications were considerably less common in patients who were still alive after more than forty years of diabetes than in patients who died before their fortieth year of diabetes.

Fifty-nine Type 1 (insulin-dependent) diabetic patients with (group I) and 59 patients without nephropathy (group II) pair-matched according to sex (30 males and 29 females), age (33 years, range 15-48) and diabetes duration (19 years, range 6-42) were followed for a period of 10 years from about 5 years before to 5 years after onset of proteinuria. The cumulative incidence of coronary heart disease was estimated, and blood pressure and serum cholesterol were followed. Within six years after onset of proteinuria the cumulative incidence of coronary heart disease was increased eight-fold in group I (40%) compared with group II (5%), (p less than 0.001). Blood pressure was higher in group I compared with group II from before onset of proteinuria (135/86 +/- 17/9 mmHg vs 129/80 +/- 15/8 mmHg, p less than 0.001), and serum cholesterol elevated from onset of proteinuria in group I (6.3 +/- 1.2 mmol/l) vs. group II (5.5 +/- 1.0 mmol/l), (p less than 0.005). Patients in group I who developed coronary heart disease had similar age (36 years, range 21-51, vs 38 years, range 21-53), sex (50% males vs. 52% males), smoking frequency (50% vs 49%), diabetes duration (22 years, range 9-39, vs 24 years, range 10-42) and serum creatinine (110 mumol/l, range 69-284, vs 108 mumol, range 72-1024) compared with patients not developing coronary heart disease.(ABSTRACT TRUNCATED AT 250 WORDS)